1. Field
The invention relates to an electromagnetic actuating apparatus. More, particularly to an actuating apparatus for internal combustion engines, and for camshaft adjustment.
2. Background
An electromagnetic actuating apparatus of the generic type is known as an apparatus for camshaft adjustment of an internal combustion engine from DE 10 2007 037 232 A1.
Apparatuses of this type for camshaft adjustment have two or more plungers which are moved in the same direction or in opposite directions or independently of one another by coil units being energized, in order to bring about an axial, predefined adjustment of the camshaft by interaction with in each case one control groove of the camshaft, as a result of which a cam can be assigned different cam tracks, in order for it to be possible, for example, to carry out a cylinder switch-off or a valve lift switchover.
The known electromagnetic actuating apparatus according to DE 10 2007 037 232 A1 has a multiple-part plunger unit which consists of a hollow plunger and an inner plunger which is received by the former, both the hollow plunger being assigned an armature which interacts with a pole core and the inner plunger which is configured as a permanent magnet being assigned a flat armature. Furthermore, a first coil unit which encloses the pole core and a second coil unit which encloses the hollow and inner plungers and is arranged axially with respect to the first coil unit in the actuating apparatus are provided. The energizing of said second coil unit brings about a movement of the flat armature of the hollow plunger in the actuating direction (it is therefore pushed out of the housing into an actuating position), whereas the armature of the inner plunger, however, remains adhering magnetically to the pole core on account of its permanent-magnetic property (the inner plunger therefore remains in its pushed-in rest position).
In order to extend the inner plunger from its retracted rest position into its actuating position, the first coil unit is energized in such a way that the armature of the inner plunger is repelled by the pole core on account of the permanent-magnetic property.
By way of a known electromagnetic actuating apparatus of this type, different penetration depths into the associated control grooves for the “part plungers” of the multiple-part plunger unit are possible in interaction with the control grooves of a camshaft, with the result that corresponding control grooves can be selected in a selective manner and moved along, with the result that the intended axial adjustment is brought about during rotation of the camshaft.
In this known actuating apparatus, however, there is the risk that the multiple-part plunger unit with a hollow and an inner plunger does not always operate in a disruption-free manner in all operating states of an internal combustion engine. Furthermore, two coil units which lead both to high material outlay and to high energy expenditure are required for the operation of said known actuating apparatus.
Accordingly, system(s) and method(s) for addressing one or more deficiencies in the prior art are presented in the detailed description below.